Refrigerating system



A in 15 1924.. 1,4903? A. R. EARNSHAW REFRIGERATING SYSTEM Filed Jan.27. 1922 INVENTOR. iH/mrfl flamsham A TTORNEYS.

Patented Apr. 15, 32%,

racer TENT REFRIGERATING- SYSTW.

Application filed January 27, 1922. Serial No. 532,12 t.

To all whom it may concern.

Be it known that I, ARTHUR R. EARN- SHAW, a citizen of the UnitedStates, residing in Wynnewood, in the county of Montgomery and State ofPennsylvania, have invented certain new and useful Improvements inRefrigerating Systems, "whereof the following is a specification,reference being had to the accompanying drawing.

This invention relates to refrigerating machines, and more particularlyto those intended for domestic use, and has for its principal object tosimplify the construction of such machines to the extent of eliminatingall valves or devices which require constant attention or manipulation,thus rendering the operation of the machine automatic and free fromerrors of adjustment. This is accomplished primarily through theparticular design and arrangement of the Well known elements of aso-called flooded type of refrigerating machine, by adapting the same todomestic use, whereby the highest point of efliciency in operation isattained, and secondarily through the use of certain details ofconstruction and new elements of a simple nature, cooperating mutuallyto accomplish, in my new design of machine all the functions necessaryin the operation of an automatic refrigerating machine, which functionswere heretofore performed only by means of regulating devices of a moreor less complex structure.

These and other objects are accomplished by virtue of my newimprovements in refrigerating systems, the preferred embodiment of whichI have shown in the accompanying drawing which illustrates in adiagrammatic manner the various elements of the invention and therelative arrangement of the correlated parts.

With reference to the drawing, 10 indicates a pump or compressor of thecharacter and design usually employed in domestic refrigeratingmachines, and 11 indicates a motor coupled thereto. The condenser, shownat 12-, is of the usual type, and is fed by the compressor through theconnection 13. The present invention is not concerned particularly withthe character or design of the compressor, motor or condenser, except tothe extent that the condenser should be designed so as to be free fromtrap cui-desacs. or recesses of any kind in which active .refrigerantmight collect instead of passing to the cooling coil. All of theessential or fundamental elements of a refrigerating system may beemployed, if desired, as my improvements relate more particularly to thecooling element, or unit, in which the refrigerant vaporizes by surfaceevaporation or boils off to secure a low temperature and to means forsecuring temperature control in a slmple manner. The discharging end ofthe condenser is connected by means of a riser 14:, a horizontal line15, and drop line 16 to a reservoir 17 at a point adjacent the upperportion of the latter. A valve casing 18 is interposed in the drop line16 at a point closely adjacent to the reservoir, and the valve casing isdesigned to house a valve mechanism of any desired construction (oneexample being a conventional form of float valve) which is so designedas to open when liquid refrigerant is present in the valve casing to theend that the liquid refrigerant may pass through the casing; past thevalve and into the reservoir 17, but which will close automatically, bygravity or otherwise, when no liquid is passing through the drop line 16or is present in the valve casing; thus preventing the return of gas orrefrigerant vapor to the condenser. A cooling coil is indicated at 19,having its lower end in communication with the reservoir, and havingsaid end extending downward into the reservoir as shown at 20,constituting the reservoir outlet, the latter being spaced for a shortdistance from the bottom of the reservoir. A restricted aperture or ventis formed in the wall of the outlet pipe 20 at a point in closeproximity to the top wall of the reservoir, but within the latter, asindicated at 21. The upper or discharge end of the cooling coil is incommunication with the lower portion of a tank, closed receptacle or thelike, 22 constituting a trap. A return pipe 23 is connected at one endto the upper portion of the trap 22, while its other end is connected tothe intake of the compressor 10. A branch 2& is provided in the return23, and is led to a pressure controlled device 25 of any suitable designwhich is adapted to operate an electric switch 26, the lattercontrolling the flow of current to the motor ll. These parts are sodesigned that when the pressure in the s stem is at a minimum. theswitch 26 will be open and consequently the motor will not run, and viceversa. Suite-hie means should be provided as part of the pressurecontrolled switch to afford adjustment so that the points of minimum andmaximum pressure at which the switch 26 is to operate, maybe variedaccording to conditions, and

subsequently fixed when the conditions be-- come unchangeable.Particular attention is directed to the design of the cooling coil,reservoir and trap 22. These elements should bear a capacity ratio tothe capacity and design of the remainder of the system, so that thereservoir 17, coil 19 and trap 22 may contain all of the activerefrigerant in the system and still leave some unoccupied space in the uper portion of the trap. If the reservoir 1 be enlarged to furnishsufficient cooling surface and then partially filled with refrigerantleaving a space to the top, approximately the same effect and actionwill be produced, without the use of either coil or trap.. By activerefrigerant, I refer to the refrigerant employed, such as ammonia, whensaid refrigerant is in a li uid state, the refrigerant being passive Wen in a gaseous state. Attention is also directed to the fact that thelower end of the drop line 16 is preferably carried between theconvolutions of the coling coil 19, so as to be in close proximitythereto. The valve casin 18 is also located as close to the cooling coias practicable.

From the foregoing description of the parts of the system, it will beseen that in operation the gaseous refrigerant is compressed in thecondenser and pipe connecttions between the compressor and the valvecasing 18 until the gas liquefies, whereupon it is permitted to fiowinto the reservoir, and thence into the cooling coil 19 and trap 22partially filling the latter. Evaporation of the liquid refrigeranttakes place, absorbing heat radiated from parts or the air surroundingthe cooling unit, and the gaseous refrigerant is then conducted by thereturn 23 to the compressor and the cycle is repeated. Practically, theoperation is more or less continuous as the eva oration of therefrigerant is constant. owever, it will be noted that an automaticthermostatic control, such as is obtainable in other machines heretoforeprovided by means of a thermostat controlled or similar device, can beeffected with the present system. As the pressure under which therefrigerant evaporates determines the temperature of the evaporation andconsequently of the refri rator in which the system is installed,variations in pressure will occur practically coincidently withvariations in tem erature, and hence the pressure controlle switchdescribed above will perform the same function as a thermostaticcontrolling device. This con trol may be rendered more sensitive anduniform by permitting the pressure operated device 25 to actuate arheostat to vary the moose? amount of current impressed upon the motor11, so that the speed of the latter may be varied in accordance with therapidity or extent of temperature changes around the cooling coil. Theresponse of the switch operating means to varying pressure will moretruly control temperature in View of the fact that all the activerefrigerant is contained at all times within the reservoir, cooling coiland trap, and these elements are all enclosed in thecooling chamber ofthe refrigerator. Consequently, all the evaporation takes place withinthese elements and as the pressure operated device 25 is incommunication with these elements at the evaporating side of the valve18, the said device will quickly and truly respond to pressure changesin the system between the compressor and the evaporating surface of therefrigerant. The provision of the vent 21 will permit the escape of anygas or refrigerant vapor into the coil 19, and thus prevent theformation of a so-called gas lock in the reservoir. The proximity of thedrop line 16 and valve casing 18 to the cooling coil 19 will ensure theliquefaction of any gaseous refrigerant that may collect in the dropline or' valve casing and thus also prevent the formation therein of agas lock.

Thus, it will be seen that I have provided a refrigerating system thatincludes a minimum number of elements. all of which are simple inconstruction and principle, so that the possibility of errors ofadjustment are eliminated and an absolute automatic action assured. Itwill furthermore be noted that the system, as herein described, isdesigned to operate at the highest point of efiiciency, since all of theactive refrigerant is contained at all times within the cooling orevaporating zone, and owing to the automatic operation of thecompressor, gaseous refrigerant is liquefied as soon as formed. Otheradvantages will readily occur to those familiar with the art to whichthis invention appertains.

Having thus described my invention, 1 claim:

1. In an automatic refrigerating apparatus, a circulatory systemincluding therein a compressor, a condenser, a reservoir to receiveactive refrigerant, a cooling coil, :1 float controlled valve to admitliquid refrigerant to the reservoir but to exclude gas, a vent to draingas accumulating in the reservoir into the cooling coil, and a trap toreceive the overflow of active refrigerant from the cooling coil andlocated thereabove.

2. An automatic refrigerating apparatus, of the flooded type, includinga circulatory system, a cooling unit therein comprising a reservoir toreceive active refrigerant, a float controlled valve to permit entranceof liquid refrigerant into the reservoir but to exclude gas, a coolingcoil located above the resereme? voir and having its intake endextending into the reservoir, and terminating adjacent the bottomthereof, said intake end having a vent near the top wall of thereservoirwithin the same to drain gas into the coil, and a tank located above thecoil and fed therefrom to receive an overflow' of refrig-- erant fromthe ooil, whereby all of the active refrigerant in the system may becontained at all times in the reservoir and coil, flooding both andpartially filling the tank.

In testimony whereof, I have hereunto signed my name at Philadelphia,Pennsylvania this 16th dav of January 1922.

ARTHUR R. EARNSHAW.

Witnesses: Y

J AMES H. BELL, E. L. FULLERTON.

